Problem: In basketball, the number of points you score is given by $3x + 2y + 1z$ where $x$ is three-pointers, $y$ is two-pointers, and $z$ is free throws (one-pointers). What is the total number of points scored by a player who makes $3$ three-pointers, $5$ two-pointers, and $6$ free throws?
Answer: A player making $3$ three-pointers, $5$ two-pointers, and $6$ free throws tells us that $x={3}$, $y={5}$, and $z={6}$. Let's substitute $x={3}$, $y={5}$, and $z={6}$ into the expression and evaluate: $\begin{aligned} &\phantom{=}3x + 2y + 1z\\\\ &= 3({3})+2({5})+1(6)\\\\ &= 9+10+6\\\\ &= {25} \end{aligned}$ A player making $3$ three-pointers, $5$ two-pointers, and $6$ free throws would score a total of ${25}$ points.